Ultrasensitive and Closed‐Tube Colorimetric Loop‐Mediated Isothermal Amplification Assay Using Carboxyl‐Modified Gold Nanoparticles

LAMP ends up in purple/red: The incorporation of 11-mercaptoundecanoic acid-modified gold nanoparticles into loop-mediated isothermal amplification (LAMP) reaction enables as few as 200 copies of a target DNA sequence to be detected by the naked eye. The color is controlled by magnesium ion-templated aggregation, and in the presence of the target, the LAMP reaction by-product pyrophosphate ion leads to particle deaggregation.